JP2018049205A - Liquid crystal projector apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal projector apparatus that controls the temperatures of display devices so that a suitable temperature balance can be maintained between the display devices even in an environment where not all the display devices can be controlled within a predetermined temperature range.SOLUTION: A liquid crystal projector apparatus comprises: a plurality of display devices 161, 221, and 251 that respectively modulate light with different color components; and a control part 27 that controls the respective temperatures of the plurality of display devices. When the temperature of the display device with the slowest temperature increasing rate, of the plurality of display devices 161, 221, and 251, does not reach a predetermined temperature, the control part 27 controls the temperatures of the other display devices to be within a predetermined range with the temperature of the display device with the slowest temperature increasing rate as a reference.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid crystal projector using a liquid crystal display element.

  In general, a liquid crystal projector device that displays a color image has three liquid crystal display elements (hereinafter simply referred to as “display elements”) provided for each of the primary color light components red (R), green (G), and blue (B). The light emitted from the light source is reflected or transmitted, and an image is projected onto the screen using a lens.

  While the liquid crystal projector is in use, the temperature of each display element rises due to the heat generated by the drive circuit and the light emitted from the light source. The display element changes its light reflection or transmission characteristics depending on the temperature. In order to maintain a high quality image, it is necessary to control the temperature of the display element. In the temperature control of the display elements, it is important to maintain the temperature balance between the display elements at the same time as controlling the temperature of each display element within a predetermined temperature range. In order to control the temperature of the display element with higher accuracy, a liquid crystal projector apparatus is disclosed in which a temperature sensor and a cooling fan are installed in each display element to control the temperature of the display element.

Japanese Patent No. 5388394

  Immediately after the liquid crystal display device is turned on, or when the ambient temperature is extremely high or extremely low, all display elements may not be controlled within the target temperature range. For example, if only one of the three display elements is out of the target temperature range, the temperature balance between the elements cannot be maintained, the color balance is lost, and the projected image quality cannot be maintained. there is a possibility.

  The present invention provides a liquid crystal projector device that controls the temperature of each display element so that a suitable temperature balance is maintained among the display elements even in an environment where all the display elements cannot be controlled within a predetermined temperature range. The purpose is to do.

  In order to achieve the above object, a liquid crystal projector device according to the present invention includes a plurality of display elements (161, 221, 251) that modulate light of different color components, and a plurality of temperature detection units that detect the temperature of each of the plurality of display elements. (165, 225, 255), a plurality of cooling units (163, 223, 253) for cooling each of the plurality of display elements, and temperatures of the plurality of display elements according to detection results of the plurality of temperature detection units by the plurality of cooling units A control unit (27) for controlling by cooling, and the control unit displays another display when the temperature of the display element having the slowest temperature rise speed among the plurality of display elements is less than a predetermined temperature. The element temperature is controlled to be within a predetermined range based on the temperature of the display element having the slowest temperature increase rate.

  In the liquid crystal projector device according to another aspect of the present invention, the cooling unit is a blower fan, and the control unit controls the number of rotations of the blower fan based on a detection result of the temperature detection unit. To do.

  According to the liquid crystal projector device of the present invention, the temperature of each display element is controlled so that a suitable temperature balance is maintained between the display elements even in an environment where all the display elements cannot be controlled within a predetermined temperature range. can do.

1 is an overall view showing a configuration of a liquid crystal projector according to an embodiment of the present invention. It is a schematic diagram which shows the structure of each modulation | alteration part and fan control apparatus in the liquid crystal projector device by one Embodiment of this invention. 6 is a graph showing a change in temperature of each display element immediately after power-on of the liquid crystal projector according to an embodiment of the present invention. 5 is a graph showing a temperature change of each display element during operation of the liquid crystal projector device according to the embodiment of the present invention.

  Embodiments of the liquid crystal projector device of the present invention will be described below with reference to the accompanying drawings. In each embodiment, three display elements (Rch display element, Bch display element, Gch display element) provided for each of red (R), green (G), and blue (B), which are primary color light components A reflection type liquid crystal projector device that reflects light emitted from a light source and projects an image on a screen using a lens will be described as an example.

<Configuration of liquid crystal projector>
With reference to FIG. 1, the structure of the liquid crystal projector apparatus used in each embodiment of the present invention will be described. The liquid crystal projector device 1 includes a light source 11 that emits white light, such as a high-pressure mercury lamp or a metal halide lamp. The light emitted from the light source 11 enters the cross dichroic mirror 12.

  The cross dichroic mirror 12 separates the three primary colors of incident illumination light into an R (red) component, a G (green) component, and a B (blue) component. The R component light that has passed through the cross dichroic mirror 12 passes through the mirror 13 and the relay lens 14, passes through the polarization beam splitter 15 serving as a polarization separation element, and enters the Rch modulation unit 16. The Rch modulation unit 16 reflects and modulates the incident R component light in accordance with the red component of the display image. The polarization-modulated reflected light is reflected by the polarization beam splitter 15 and is incident on the color synthesis prism 17 from one side surface portion.

  On the other hand, the G component light and the B component light that have passed through the cross dichroic mirror 12 are incident on the dichroic mirror 19 via the mirror 18. The dichroic mirror 19 separates the incident G component light and B component light into G component light and B component light. The G component light reflected by the dichroic mirror 19 passes through the relay lens 20, passes through the polarization beam splitter 21 serving as a polarization separation element, and enters the Gch modulation unit 22. The Gch modulator 22 reflects and modulates the incident G component light according to the green component of the display image. The polarization-modulated reflected light is reflected by the polarization beam splitter 21 and enters the color synthesis prism 17 from the rear surface portion.

  Then, the B component light transmitted through the dichroic mirror 19 passes through the relay lens 23, passes through the polarization beam splitter 24 serving as a polarization separation element, and enters the Bch modulation unit 25. The Bch modulation unit 25 reflects and modulates the incident B component light according to the polarization modulation according to the blue component of the display image. The polarization-modulated reflected light is reflected by the polarization beam splitter 24 and enters the color synthesis prism 17 from the other side surface portion.

  The color combining prism 17 combines the R component light incident from one side surface portion, the G component light incident from the rear surface portion, and the B component light incident from the other side surface portion, and emits them from the front surface portion. The illumination light emitted from the color synthesizing prism 17 is incident on a projection lens 26 serving as a projection optical system. The projection lens 26 projects the incident illumination light toward a screen (not shown), forms an image, and displays an image.

  Detailed configurations of the Rch modulation unit 16, the Gch modulation unit 22, and the Bch modulation unit 25 will be described with reference to the schematic diagram of FIG. The Rch modulation unit 16 cools the Rch display element 161 that modulates the R signal component, the Rch heat sink 162 that radiates the heat of the Rch display element 161, and the Rch display element 161 and the Rch heat sink 162. The Rch fan 163, the Rch duct 164 for sending the wind generated by the operation of the Rch fan 163 to the Rch display element 161 and the Rch heat sink 162, and the Rch temperature for detecting the temperature of the Rch display element 161 Sensor 165. The Rch fan 163 functions as a cooling unit for the Rch display element 161.

  The Gch modulation unit 22 cools the Gch display element 221 that modulates the G signal component, the Gch heat sink 222 that radiates the heat of the Gch display element 221, and the Gch display element 221 and the Gch heat sink 222. Gch fan 223, Gch duct 224 for sending wind generated by the operation of Gch fan 223 to Gch display element 221 and Gch heat sink 222, and Gch temperature for detecting the temperature of Gch display element 221 Sensor 225. The Gch fan 223 functions as a cooling unit for the Gch display element 221.

  The Bch modulation unit 25 cools the Bch display element 251 that modulates the B signal component, the Bch heat sink 252 that radiates heat from the Bch display element 251, and the Bch display element 251 and the Bch heat sink 252. Bch fan 253, Bch duct 254 for sending wind generated by the operation of Bch fan 253 to Bch display element 251 and Bch heat sink 252, and Bch temperature for detecting the temperature of Bch display element 251 Sensor 255. The Bch fan 253 functions as a cooling unit for the Bch display element 251.

  The Rch fan 163, the Gch fan 223, and the Bch fan 253 are configured by a sirocco fan, an axial fan, or the like. Further, the Rch temperature sensor 165, the Gch temperature sensor 225, and the Bch temperature sensor 255 are composed of, for example, a thermistor.

  Further, in the liquid crystal projector device 1, a control unit 27 that controls the rotational speeds of the Rch fan 163, the Gch fan 223, and the Bch fan 253 is installed. Based on the temperatures detected by the temperature sensors 165, 225, and 255, the control unit 27 sets the rotation speeds of the fans 163, 223, and 253 so that the display elements 161, 221 and 251 have a desired temperature. Control.

<First Embodiment>
A temperature control operation of each of the display elements 161, 221 and 251 in the liquid crystal projector device 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 3 is a graph showing the temperature change of each display element immediately after the liquid crystal projector device 1 is powered on.

  When the power of the liquid crystal projector device 1 is turned on and the temperature of each display element is lower than the first set temperature, the control unit 27 stops the fan in order to control the temperature of the display element to be raised. The “first set temperature” is, for example, “60 ° C.”. Each display element generates heat due to heat generated by the drive circuit of the display element itself or light incident from the light source 11, and the temperature rises. At this time, the temperature increase rate may be different between the display elements. This is due to the fact that the magnitude of the energy of light applied to the display element differs depending on the color component light. The magnitude of the energy of each color component light varies depending on the characteristics of the light source 11, but generally the energy of the G component light is the largest. Therefore, the temperature rise rate of the Gch display element 221 is faster than the Rch display element 161 and the Bch display element 251.

For example, as shown in FIG. 3, the temperature of the Gch display element 221 rises as indicated by a thin one-dot chain line G ₀ , whereas the temperature of the Bch display element 251 increases as indicated by a thin two-dot chain line B ₀ . The temperature of the Rch display element 161 rises at a slower rate as indicated by the solid line R. Therefore, the temperature difference between the display element 161 for Rch, the display element 221 for Gch, and the display element 251 for Bch increases, and an appropriate temperature balance cannot be maintained among the display elements, so that the color balance is lost, and the projected image There is a high possibility of quality degradation.

  Therefore, when the temperature of the Rch display element 251 having the slowest temperature rise speed among the three display elements is less than the first set temperature, the control unit 27 determines the temperature of the Gch display element 221 and the Bch display element. The Gch fan 223 and the Bch fan 253 are driven and controlled so that the temperature of 251 falls within a predetermined range based on the temperature of the Rch display element 161. The predetermined range is, for example, within ± 5 ° C., the temperature of the Gch display element 221 is within ± 5 ° C., and similarly the temperature of the Bch display element 251 is ± 5 ° C. with respect to the temperature of the Rch display element 161. Control each to within.

By controlling in this way, as shown in FIG. 3, the temperature of the Gch display element 221 becomes as indicated by a thick one-dot chain line G ₁ , and the Rch is higher than when the Gch fan 223 is not driven (G ₀ ). It approaches the solid line R indicating the temperature rise of the display element 161 for use. Further, the temperature of the Bch display element 251 becomes a thick two-dot chain line B ₁ , and the solid line R indicating the temperature rise of the Rch display element 161 is higher than when the Bch fan 253 is not driven (B ₀ ). Get closer to. Therefore, even when the temperature of each display element immediately after power-on is likely to vary, the temperature difference between the display elements is reduced, and the quality of the projected image can be improved by maintaining the temperature balance between the display elements at an early stage. .

  Thereafter, when the temperature of the Rch display element 161 becomes higher than the first set temperature, the control unit 27 controls the temperature of each display element to be within a predetermined temperature range. The predetermined temperature range is, for example, in the range of 60 ° C to 70 ° C.

  This embodiment has been described on the assumption that the temperature rise rate of the Rch display element 161 after power-on is slower than that of the Gch display element 221 and the Bch display element 251, but the temperature rise rate is not limited to this. The temperature of the other display element may be controlled based on the temperature of the display element of the slowest channel. For example, when the temperature rise rate of the Gch display element 221 is the slowest, the temperatures of the other display elements are controlled based on the temperature of the Gch display element 221 until the temperature of the Gch display element 221 reaches the first set temperature. To do. Similarly, when the temperature rise rate of the Bch display element 251 is the slowest, the temperatures of the other display elements are set on the basis of the temperature of the Bch display element 251 until the temperature of the Bch display element 251 reaches the first set temperature. Control. The difference between the display elements of the temperature rise rate after power-on may be compared in advance by experiment.

Second Embodiment
The temperature of the display element is controlled by being cooled by air blown by a fan. However, if the environmental temperature is extremely high or extremely low, the display element may not be controlled within the target temperature range. is there.

  FIG. 4 is a diagram illustrating a temperature change of each display element when the environmental temperature is changed in a state where each display element is controlled to be within a target temperature range of 60 to 70 ° C.

  X, Y, and Z represent display elements of different colors, and correspond to any of the Rch display element 161, the Gch display element 221, and the Bch display element 251, respectively. The temperature of the display element Z cannot be maintained within the target temperature range below the environmental temperature a, and decreases with the environmental temperature to a temperature lower than 60 ° C., which is the lower limit of the target temperature range. On the other hand, at the environmental temperature a, the display elements X and Y can be controlled within the target temperature range. However, if the display elements X and Y are controlled so as to be within the target temperature range when the ambient temperature is less than or equal to the environmental temperature a, the temperature difference between the display element Z and the display elements X and Y becomes large, and the temperature balance between the display elements. Will not be able to keep. If the temperature balance between the display elements cannot be maintained, the color balance may be lost. For this reason, below the environmental temperature a, the temperature of the display elements X and Y is controlled to be within a predetermined range with the temperature of the display element Z having the lowest temperature as a reference. Specifically, the fan for the display element Z is stopped, and the temperature of the display element X and the display element Y is controlled to be within ± 5 ° C. with respect to the temperature of the display element Z, for example.

  Further, the temperature of the display element X cannot be maintained within the target temperature range at the environmental temperature b or higher, and rises with the environmental temperature and is higher than 70 ° C. which is the upper limit of the target temperature range. On the other hand, at the environmental temperature b, the display elements Y and Z can be controlled within the target temperature range. However, if the display elements Y and Z are controlled so as to be within the target temperature range when the ambient temperature is equal to or higher than the environmental temperature b, the temperature difference between the display element X and the display elements Y and Z becomes large, and the temperature balance between the display elements. Will not be able to keep. If the temperature balance between the display elements cannot be maintained, the color balance may be lost. For this reason, at the environmental temperature b or higher, the temperatures of the display elements Y and Z are controlled to be within a predetermined range based on the temperature of the display element X having the highest temperature. Specifically, the rotation speed of the fan for the display element X is kept at the maximum, and the temperature of the display element Y and the display element Z is controlled to be within ± 5 ° C. with respect to the temperature of the display element X, for example.

  As a result, even when the temperature of at least one of the display elements cannot be maintained within the target temperature range, the temperature difference between the display elements can be reduced, and the color balance collapse can be reduced. it can.

  When each display element can be controlled within the target temperature range, in addition to controlling the temperature of each display element to be within the predetermined temperature range, other displays are performed based on the predetermined display element temperature. You may make it control the temperature of an element. For example, the temperature of the Gch display element 221 that most affects the image quality is controlled to be 60 to 70 ° C., and the temperatures of the Rch display element 161 and the Bch display element 251 are the temperatures of the Gch display element 221. In contrast, the temperature may be controlled to be within ± 5 ° C. By controlling in this way, the temperature balance of each channel can be controlled with higher accuracy.

  In the first and second embodiments described above, an example is shown in which the temperature of the display element of each channel is controlled to be as high as possible. However, the control target temperature range may be changed for each display element. In general, the display element for Bch reflects light containing a large amount of ultraviolet components, so it deteriorates faster than other display elements. Therefore, the display element for Bch is cooled to a slightly lower temperature than other display elements. Can extend the lifespan. Therefore, the target set temperature of the Bch display element may be controlled to be slightly lower (for example, about 5 ° C.) than the Rch display element and the Gch display element.

  In the first and second embodiments described above, the cooling unit has been described as a configuration in which air is sent by a fan. However, the cooling unit is not limited to the air cooling type, and a water cooling type is also applicable.

  In the first and second embodiments described above, the color components are described as three colors of red, green, and blue. However, the present invention is not limited to this, and for example, yellow may be added to obtain four colors.

DESCRIPTION OF SYMBOLS 1 Liquid crystal projector device 2 Screen 11 Light source 12, 19 Cross dichroic mirror 13, 18 Mirror 14, 20, 23 Relay lens 15, 21, 24 Polarization beam splitter 16 Rch modulation part 17 Color synthesis prism 22 Gch modulation part 25 Bch modulation part 26 Projection lens 27 Control unit 161 Rch display element 162 Rch heat sink 163 Rch fan 164 Rch duct 165 Rch temperature sensor 221 Gch display element 222 Gch heat sink 223 Gch fan 224 Gch duct 225 Gch temperature sensor 251 Bch display element 252 Bch heat sink 253 Bch fan 254 Bch duct 255 Bch temperature sensor

Claims (2)

A plurality of display elements each modulating light of different color components;
A plurality of temperature detectors for detecting the temperature of each of the plurality of display elements;
A plurality of cooling units for cooling each of the plurality of display elements;
A control unit that controls the cooling of the plurality of display elements according to the detection results of the plurality of temperature detection units by the cooling units.
The controller is
Among the plurality of display elements, when the temperature of the display element having the slowest temperature increase rate is less than the predetermined temperature, the temperature of the other display element is determined based on the temperature of the display element having the slowest temperature increase rate. A liquid crystal projector device that is controlled to be within a range. The liquid crystal projector device according to claim 1, wherein the cooling unit is a blower fan, and the control unit controls a rotation speed of the blower fan based on a detection result of the temperature detection unit.

Images